Stem Sawfly, family Cephidae, order Hymenoptera, (no taxon) Symphyta: Sawflies, Horntails, and Wood Wasps
No taxon recognized by BugGuide at this time, but Symphyta is essentially a suborder of Order Hymenoptera (Bees and Wasps).
This species is almost unique in its approach to sexual congress: they get it on face-to-face and belly-to-belly. Fast.
This shot appears in a German checklist of Symphyta of the world.